/* -*- c -*- --------------------------------------------------------------- * * * linux/fs/autofs/root.c * * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved * Copyright 1999-2000 Jeremy Fitzhardinge * Copyright 2001-2006 Ian Kent * * This file is part of the Linux kernel and is made available under * the terms of the GNU General Public License, version 2, or at your * option, any later version, incorporated herein by reference. * * ------------------------------------------------------------------------- */ #include #include #include #include #include #include #include #include #include "autofs_i.h" static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *); static int autofs4_dir_unlink(struct inode *,struct dentry *); static int autofs4_dir_rmdir(struct inode *,struct dentry *); static int autofs4_dir_mkdir(struct inode *,struct dentry *,int); static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long); static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long); static int autofs4_dir_open(struct inode *inode, struct file *file); static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *); static void *autofs4_follow_link(struct dentry *, struct nameidata *); #define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) #define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE) const struct file_operations autofs4_root_operations = { .open = dcache_dir_open, .release = dcache_dir_close, .read = generic_read_dir, .readdir = dcache_readdir, .llseek = dcache_dir_lseek, .unlocked_ioctl = autofs4_root_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = autofs4_root_compat_ioctl, #endif }; const struct file_operations autofs4_dir_operations = { .open = autofs4_dir_open, .release = dcache_dir_close, .read = generic_read_dir, .readdir = dcache_readdir, .llseek = dcache_dir_lseek, }; const struct inode_operations autofs4_indirect_root_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, .symlink = autofs4_dir_symlink, .mkdir = autofs4_dir_mkdir, .rmdir = autofs4_dir_rmdir, }; const struct inode_operations autofs4_direct_root_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, .mkdir = autofs4_dir_mkdir, .rmdir = autofs4_dir_rmdir, .follow_link = autofs4_follow_link, }; const struct inode_operations autofs4_dir_inode_operations = { .lookup = autofs4_lookup, .unlink = autofs4_dir_unlink, .symlink = autofs4_dir_symlink, .mkdir = autofs4_dir_mkdir, .rmdir = autofs4_dir_rmdir, }; static void autofs4_add_active(struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); if (ino) { spin_lock(&sbi->lookup_lock); if (!ino->active_count) { if (list_empty(&ino->active)) list_add(&ino->active, &sbi->active_list); } ino->active_count++; spin_unlock(&sbi->lookup_lock); } return; } static void autofs4_del_active(struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); if (ino) { spin_lock(&sbi->lookup_lock); ino->active_count--; if (!ino->active_count) { if (!list_empty(&ino->active)) list_del_init(&ino->active); } spin_unlock(&sbi->lookup_lock); } return; } static unsigned int autofs4_need_mount(unsigned int flags) { unsigned int res = 0; if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS)) res = 1; return res; } static int autofs4_dir_open(struct inode *inode, struct file *file) { struct dentry *dentry = file->f_path.dentry; struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); DPRINTK("file=%p dentry=%p %.*s", file, dentry, dentry->d_name.len, dentry->d_name.name); if (autofs4_oz_mode(sbi)) goto out; /* * An empty directory in an autofs file system is always a * mount point. The daemon must have failed to mount this * during lookup so it doesn't exist. This can happen, for * example, if user space returns an incorrect status for a * mount request. Otherwise we're doing a readdir on the * autofs file system so just let the libfs routines handle * it. */ spin_lock(&dcache_lock); if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { spin_unlock(&dcache_lock); return -ENOENT; } spin_unlock(&dcache_lock); out: return dcache_dir_open(inode, file); } static int try_to_fill_dentry(struct dentry *dentry, int flags) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); int status; DPRINTK("dentry=%p %.*s ino=%p", dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode); /* * Wait for a pending mount, triggering one if there * isn't one already */ if (dentry->d_inode == NULL) { DPRINTK("waiting for mount name=%.*s", dentry->d_name.len, dentry->d_name.name); status = autofs4_wait(sbi, dentry, NFY_MOUNT); DPRINTK("mount done status=%d", status); /* Turn this into a real negative dentry? */ if (status == -ENOENT) { spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); return status; } else if (status) { /* Return a negative dentry, but leave it "pending" */ return status; } /* Trigger mount for path component or follow link */ } else if (ino->flags & AUTOFS_INF_PENDING || autofs4_need_mount(flags)) { DPRINTK("waiting for mount name=%.*s", dentry->d_name.len, dentry->d_name.name); spin_lock(&sbi->fs_lock); ino->flags |= AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); status = autofs4_wait(sbi, dentry, NFY_MOUNT); DPRINTK("mount done status=%d", status); if (status) { spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); return status; } } /* Initialize expiry counter after successful mount */ ino->last_used = jiffies; spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); return 0; } /* For autofs direct mounts the follow link triggers the mount */ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); int oz_mode = autofs4_oz_mode(sbi); unsigned int lookup_type; int status; DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d", dentry, dentry->d_name.len, dentry->d_name.name, oz_mode, nd->flags); /* * For an expire of a covered direct or offset mount we need * to break out of follow_down() at the autofs mount trigger * (d_mounted--), so we can see the expiring flag, and manage * the blocking and following here until the expire is completed. */ if (oz_mode) { spin_lock(&sbi->fs_lock); if (ino->flags & AUTOFS_INF_EXPIRING) { spin_unlock(&sbi->fs_lock); /* Follow down to our covering mount. */ if (!follow_down(&nd->path)) goto done; goto follow; } spin_unlock(&sbi->fs_lock); goto done; } /* If an expire request is pending everyone must wait. */ autofs4_expire_wait(dentry); /* We trigger a mount for almost all flags */ lookup_type = autofs4_need_mount(nd->flags); spin_lock(&sbi->fs_lock); spin_lock(&dcache_lock); if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) { spin_unlock(&dcache_lock); spin_unlock(&sbi->fs_lock); goto follow; } /* * If the dentry contains directories then it is an autofs * multi-mount with no root mount offset. So don't try to * mount it again. */ if (ino->flags & AUTOFS_INF_PENDING || (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) { spin_unlock(&dcache_lock); spin_unlock(&sbi->fs_lock); status = try_to_fill_dentry(dentry, nd->flags); if (status) goto out_error; goto follow; } spin_unlock(&dcache_lock); spin_unlock(&sbi->fs_lock); follow: /* * If there is no root mount it must be an autofs * multi-mount with no root offset so we don't need * to follow it. */ if (d_mountpoint(dentry)) { if (!autofs4_follow_mount(&nd->path)) { status = -ENOENT; goto out_error; } } done: return NULL; out_error: path_put(&nd->path); return ERR_PTR(status); } /* * Revalidate is called on every cache lookup. Some of those * cache lookups may actually happen while the dentry is not * yet completely filled in, and revalidate has to delay such * lookups.. */ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd) { struct inode *dir = dentry->d_parent->d_inode; struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); int oz_mode = autofs4_oz_mode(sbi); int flags = nd ? nd->flags : 0; int status = 1; /* Pending dentry */ spin_lock(&sbi->fs_lock); if (autofs4_ispending(dentry)) { /* The daemon never causes a mount to trigger */ spin_unlock(&sbi->fs_lock); if (oz_mode) return 1; /* * If the directory has gone away due to an expire * we have been called as ->d_revalidate() and so * we need to return false and proceed to ->lookup(). */ if (autofs4_expire_wait(dentry) == -EAGAIN) return 0; /* * A zero status is success otherwise we have a * negative error code. */ status = try_to_fill_dentry(dentry, flags); if (status == 0) return 1; return status; } spin_unlock(&sbi->fs_lock); /* Negative dentry.. invalidate if "old" */ if (dentry->d_inode == NULL) return 0; /* Check for a non-mountpoint directory with no contents */ spin_lock(&dcache_lock); if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) { DPRINTK("dentry=%p %.*s, emptydir", dentry, dentry->d_name.len, dentry->d_name.name); spin_unlock(&dcache_lock); /* The daemon never causes a mount to trigger */ if (oz_mode) return 1; /* * A zero status is success otherwise we have a * negative error code. */ status = try_to_fill_dentry(dentry, flags); if (status == 0) return 1; return status; } spin_unlock(&dcache_lock); return 1; } void autofs4_dentry_release(struct dentry *de) { struct autofs_info *inf; DPRINTK("releasing %p", de); inf = autofs4_dentry_ino(de); de->d_fsdata = NULL; if (inf) { struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb); if (sbi) { spin_lock(&sbi->lookup_lock); if (!list_empty(&inf->active)) list_del(&inf->active); if (!list_empty(&inf->expiring)) list_del(&inf->expiring); spin_unlock(&sbi->lookup_lock); } inf->dentry = NULL; inf->inode = NULL; autofs4_free_ino(inf); } } /* For dentries of directories in the root dir */ static const struct dentry_operations autofs4_root_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; /* For other dentries */ static const struct dentry_operations autofs4_dentry_operations = { .d_revalidate = autofs4_revalidate, .d_release = autofs4_dentry_release, }; static struct dentry *autofs4_lookup_active(struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct dentry *parent = dentry->d_parent; struct qstr *name = &dentry->d_name; unsigned int len = name->len; unsigned int hash = name->hash; const unsigned char *str = name->name; struct list_head *p, *head; spin_lock(&dcache_lock); spin_lock(&sbi->lookup_lock); head = &sbi->active_list; list_for_each(p, head) { struct autofs_info *ino; struct dentry *active; struct qstr *qstr; ino = list_entry(p, struct autofs_info, active); active = ino->dentry; spin_lock(&active->d_lock); /* Already gone? */ if (atomic_read(&active->d_count) == 0) goto next; qstr = &active->d_name; if (active->d_name.hash != hash) goto next; if (active->d_parent != parent) goto next; if (qstr->len != len) goto next; if (memcmp(qstr->name, str, len)) goto next; if (d_unhashed(active)) { dget(active); spin_unlock(&active->d_lock); spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); return active; } next: spin_unlock(&active->d_lock); } spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); return NULL; } static struct dentry *autofs4_lookup_expiring(struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); struct dentry *parent = dentry->d_parent; struct qstr *name = &dentry->d_name; unsigned int len = name->len; unsigned int hash = name->hash; const unsigned char *str = name->name; struct list_head *p, *head; spin_lock(&dcache_lock); spin_lock(&sbi->lookup_lock); head = &sbi->expiring_list; list_for_each(p, head) { struct autofs_info *ino; struct dentry *expiring; struct qstr *qstr; ino = list_entry(p, struct autofs_info, expiring); expiring = ino->dentry; spin_lock(&expiring->d_lock); /* Bad luck, we've already been dentry_iput */ if (!expiring->d_inode) goto next; qstr = &expiring->d_name; if (expiring->d_name.hash != hash) goto next; if (expiring->d_parent != parent) goto next; if (qstr->len != len) goto next; if (memcmp(qstr->name, str, len)) goto next; if (d_unhashed(expiring)) { dget(expiring); spin_unlock(&expiring->d_lock); spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); return expiring; } next: spin_unlock(&expiring->d_lock); } spin_unlock(&sbi->lookup_lock); spin_unlock(&dcache_lock); return NULL; } /* Lookups in the root directory */ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd) { struct autofs_sb_info *sbi; struct autofs_info *ino; struct dentry *expiring, *active; int oz_mode; DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name); /* File name too long to exist */ if (dentry->d_name.len > NAME_MAX) return ERR_PTR(-ENAMETOOLONG); sbi = autofs4_sbi(dir->i_sb); oz_mode = autofs4_oz_mode(sbi); DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d", current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode); active = autofs4_lookup_active(dentry); if (active) { dentry = active; ino = autofs4_dentry_ino(dentry); } else { /* * Mark the dentry incomplete but don't hash it. We do this * to serialize our inode creation operations (symlink and * mkdir) which prevents deadlock during the callback to * the daemon. Subsequent user space lookups for the same * dentry are placed on the wait queue while the daemon * itself is allowed passage unresticted so the create * operation itself can then hash the dentry. Finally, * we check for the hashed dentry and return the newly * hashed dentry. */ dentry->d_op = &autofs4_root_dentry_operations; /* * And we need to ensure that the same dentry is used for * all following lookup calls until it is hashed so that * the dentry flags are persistent throughout the request. */ ino = autofs4_init_ino(NULL, sbi, 0555); if (!ino) return ERR_PTR(-ENOMEM); dentry->d_fsdata = ino; ino->dentry = dentry; autofs4_add_active(dentry); d_instantiate(dentry, NULL); } if (!oz_mode) { mutex_unlock(&dir->i_mutex); expiring = autofs4_lookup_expiring(dentry); if (expiring) { /* * If we are racing with expire the request might not * be quite complete but the directory has been removed * so it must have been successful, so just wait for it. */ autofs4_expire_wait(expiring); autofs4_del_expiring(expiring); dput(expiring); } spin_lock(&sbi->fs_lock); ino->flags |= AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); if (dentry->d_op && dentry->d_op->d_revalidate) (dentry->d_op->d_revalidate)(dentry, nd); mutex_lock(&dir->i_mutex); } /* * If we are still pending, check if we had to handle * a signal. If so we can force a restart.. */ if (ino->flags & AUTOFS_INF_PENDING) { /* See if we were interrupted */ if (signal_pending(current)) { sigset_t *sigset = ¤t->pending.signal; if (sigismember (sigset, SIGKILL) || sigismember (sigset, SIGQUIT) || sigismember (sigset, SIGINT)) { if (active) dput(active); return ERR_PTR(-ERESTARTNOINTR); } } if (!oz_mode) { spin_lock(&sbi->fs_lock); ino->flags &= ~AUTOFS_INF_PENDING; spin_unlock(&sbi->fs_lock); } } /* * If this dentry is unhashed, then we shouldn't honour this * lookup. Returning ENOENT here doesn't do the right thing * for all system calls, but it should be OK for the operations * we permit from an autofs. */ if (!oz_mode && d_unhashed(dentry)) { /* * A user space application can (and has done in the past) * remove and re-create this directory during the callback. * This can leave us with an unhashed dentry, but a * successful mount! So we need to perform another * cached lookup in case the dentry now exists. */ struct dentry *parent = dentry->d_parent; struct dentry *new = d_lookup(parent, &dentry->d_name); if (new != NULL) dentry = new; else dentry = ERR_PTR(-ENOENT); if (active) dput(active); return dentry; } if (active) return active; return NULL; } static int autofs4_dir_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); struct autofs_info *p_ino; struct inode *inode; char *cp; DPRINTK("%s <- %.*s", symname, dentry->d_name.len, dentry->d_name.name); if (!autofs4_oz_mode(sbi)) return -EACCES; ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555); if (!ino) return -ENOMEM; autofs4_del_active(dentry); ino->size = strlen(symname); cp = kmalloc(ino->size + 1, GFP_KERNEL); if (!cp) { if (!dentry->d_fsdata) kfree(ino); return -ENOMEM; } strcpy(cp, symname); inode = autofs4_get_inode(dir->i_sb, ino); if (!inode) { kfree(cp); if (!dentry->d_fsdata) kfree(ino); return -ENOMEM; } d_add(dentry, inode); if (dir == dir->i_sb->s_root->d_inode) dentry->d_op = &autofs4_root_dentry_operations; else dentry->d_op = &autofs4_dentry_operations; dentry->d_fsdata = ino; ino->dentry = dget(dentry); atomic_inc(&ino->count); p_ino = autofs4_dentry_ino(dentry->d_parent); if (p_ino && dentry->d_parent != dentry) atomic_inc(&p_ino->count); ino->inode = inode; ino->u.symlink = cp; dir->i_mtime = CURRENT_TIME; return 0; } /* * NOTE! * * Normal filesystems would do a "d_delete()" to tell the VFS dcache * that the file no longer exists. However, doing that means that the * VFS layer can turn the dentry into a negative dentry. We don't want * this, because the unlink is probably the result of an expire. * We simply d_drop it and add it to a expiring list in the super block, * which allows the dentry lookup to check for an incomplete expire. * * If a process is blocked on the dentry waiting for the expire to finish, * it will invalidate the dentry and try to mount with a new one. * * Also see autofs4_dir_rmdir().. */ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); struct autofs_info *p_ino; /* This allows root to remove symlinks */ if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) return -EACCES; if (atomic_dec_and_test(&ino->count)) { p_ino = autofs4_dentry_ino(dentry->d_parent); if (p_ino && dentry->d_parent != dentry) atomic_dec(&p_ino->count); } dput(ino->dentry); dentry->d_inode->i_size = 0; clear_nlink(dentry->d_inode); dir->i_mtime = CURRENT_TIME; spin_lock(&dcache_lock); autofs4_add_expiring(dentry); spin_lock(&dentry->d_lock); __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); return 0; } static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); struct autofs_info *p_ino; DPRINTK("dentry %p, removing %.*s", dentry, dentry->d_name.len, dentry->d_name.name); if (!autofs4_oz_mode(sbi)) return -EACCES; spin_lock(&dcache_lock); if (!list_empty(&dentry->d_subdirs)) { spin_unlock(&dcache_lock); return -ENOTEMPTY; } autofs4_add_expiring(dentry); spin_lock(&dentry->d_lock); __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&dcache_lock); if (atomic_dec_and_test(&ino->count)) { p_ino = autofs4_dentry_ino(dentry->d_parent); if (p_ino && dentry->d_parent != dentry) atomic_dec(&p_ino->count); } dput(ino->dentry); dentry->d_inode->i_size = 0; clear_nlink(dentry->d_inode); if (dir->i_nlink) drop_nlink(dir); return 0; } static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode) { struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb); struct autofs_info *ino = autofs4_dentry_ino(dentry); struct autofs_info *p_ino; struct inode *inode; if (!autofs4_oz_mode(sbi)) return -EACCES; DPRINTK("dentry %p, creating %.*s", dentry, dentry->d_name.len, dentry->d_name.name); ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555); if (!ino) return -ENOMEM; autofs4_del_active(dentry); inode = autofs4_get_inode(dir->i_sb, ino); if (!inode) { if (!dentry->d_fsdata) kfree(ino); return -ENOMEM; } d_add(dentry, inode); if (dir == dir->i_sb->s_root->d_inode) dentry->d_op = &autofs4_root_dentry_operations; else dentry->d_op = &autofs4_dentry_operations; dentry->d_fsdata = ino; ino->dentry = dget(dentry); atomic_inc(&ino->count); p_ino = autofs4_dentry_ino(dentry->d_parent); if (p_ino && dentry->d_parent != dentry) atomic_inc(&p_ino->count); ino->inode = inode; inc_nlink(dir); dir->i_mtime = CURRENT_TIME; return 0; } /* Get/set timeout ioctl() operation */ #ifdef CONFIG_COMPAT static inline int autofs4_compat_get_set_timeout(struct autofs_sb_info *sbi, compat_ulong_t __user *p) { int rv; unsigned long ntimeout; if ((rv = get_user(ntimeout, p)) || (rv = put_user(sbi->exp_timeout/HZ, p))) return rv; if (ntimeout > UINT_MAX/HZ) sbi->exp_timeout = 0; else sbi->exp_timeout = ntimeout * HZ; return 0; } #endif static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi, unsigned long __user *p) { int rv; unsigned long ntimeout; if ((rv = get_user(ntimeout, p)) || (rv = put_user(sbi->exp_timeout/HZ, p))) return rv; if (ntimeout > ULONG_MAX/HZ) sbi->exp_timeout = 0; else sbi->exp_timeout = ntimeout * HZ; return 0; } /* Return protocol version */ static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p) { return put_user(sbi->version, p); } /* Return protocol sub version */ static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p) { return put_user(sbi->sub_version, p); } /* * Tells the daemon whether it can umount the autofs mount. */ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p) { int status = 0; if (may_umount(mnt)) status = 1; DPRINTK("returning %d", status); status = put_user(status, p); return status; } /* Identify autofs4_dentries - this is so we can tell if there's an extra dentry refcount or not. We only hold a refcount on the dentry if its non-negative (ie, d_inode != NULL) */ int is_autofs4_dentry(struct dentry *dentry) { return dentry && dentry->d_inode && (dentry->d_op == &autofs4_root_dentry_operations || dentry->d_op == &autofs4_dentry_operations) && dentry->d_fsdata != NULL; } /* * ioctl()'s on the root directory is the chief method for the daemon to * generate kernel reactions */ static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) { struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb); void __user *p = (void __user *)arg; DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u", cmd,arg,sbi,task_pgrp_nr(current)); if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) || _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT) return -ENOTTY; if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) return -EPERM; switch(cmd) { case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */ return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0); case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */ return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT); case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */ autofs4_catatonic_mode(sbi); return 0; case AUTOFS_IOC_PROTOVER: /* Get protocol version */ return autofs4_get_protover(sbi, p); case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */ return autofs4_get_protosubver(sbi, p); case AUTOFS_IOC_SETTIMEOUT: return autofs4_get_set_timeout(sbi, p); #ifdef CONFIG_COMPAT case AUTOFS_IOC_SETTIMEOUT32: return autofs4_compat_get_set_timeout(sbi, p); #endif case AUTOFS_IOC_ASKUMOUNT: return autofs4_ask_umount(filp->f_path.mnt, p); /* return a single thing to expire */ case AUTOFS_IOC_EXPIRE: return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p); /* same as above, but can send multiple expires through pipe */ case AUTOFS_IOC_EXPIRE_MULTI: return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p); default: return -ENOSYS; } } static DEFINE_MUTEX(autofs4_ioctl_mutex); static long autofs4_root_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { long ret; struct inode *inode = filp->f_dentry->d_inode; mutex_lock(&autofs4_ioctl_mutex); ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); mutex_unlock(&autofs4_ioctl_mutex); return ret; } #ifdef CONFIG_COMPAT static long autofs4_root_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = filp->f_path.dentry->d_inode; int ret; mutex_lock(&autofs4_ioctl_mutex); if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL) ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg); else ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, (unsigned long)compat_ptr(arg)); mutex_unlock(&autofs4_ioctl_mutex); return ret; } #endif